list去掉重复元素

需求: 有list 里面含有重复元素，要求去掉重复元素：

solution 1:

>>> a
[1, 2, 2, 1, 3, 4, 5, 6, 5]
>>> set(a)
set([1, 2, 3, 4, 5, 6])
>>> list(set(a))
[1, 2, 3, 4, 5, 6]

set操作是 Build an unordered collection of unique elements.

solution 2:

>>> a
[1, 2, 2, 1, 3, 4, 5, 6, 5]
>>> b={}
>>> b.fromkeys(a)
{1: None, 2: None, 3: None, 4: None, 5: None, 6: None}
>>> b.fromkeys(a).keys()
[1, 2, 3, 4, 5, 6]

b.fromkeys(S,[v])是以 s序列中的元素为key v中的元素为value生成字典。 v默认为none